# CVE-2025-53476: Denial of service in OpenPLC v3

> An attacker can cause a denial of service in OpenPLC's ModbusTCP server by opening a series of TCP connections, preventing subsequent request processing.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 7 Oct 2025
- **Updated:** 3 Nov 2025
- **Also known as:** GHSA-pm3x-2fvm-pvp8

## What is CVE-2025-53476?

CVE-2025-53476 is a medium-severity denial of service vulnerability in OpenPLC_v3, published on 7 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

A denial of service vulnerability exists in the ModbusTCP server functionality of OpenPLC _v3 a931181e8b81e36fadf7b74d5cba99b73c3f6d58. A specially crafted series of network connections can lead to the server not processing subsequent Modbus requests. An attacker can open a series of TCP connections to trigger this vulnerability.

Weakness: CWE-775 (Missing Release of File Descriptor or Handle after Effective Lifetime)

## Which versions are affected by CVE-2025-53476?


## How do I fix CVE-2025-53476?

No fix has been published for CVE-2025-53476 yet. Limit exposure of the affected software until one is available.

## Is CVE-2025-53476 being exploited?

There is no known exploitation of CVE-2025-53476 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-53476 and fix it if it is affected.

What it is: CVE-2025-53476 is a medium-severity denial of service vulnerability in OpenPLC_v3, published on 7 Oct 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-53476 in the wild and no public exploit code.

Affected product: OpenPLC_v3. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-53476/ (Markdown: https://insights.sbomify.com/CVE-2025-53476/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-53476
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-53476
- OSV: https://osv.dev/vulnerability/CVE-2025-53476

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-53476/
Summaries are generated and may contain mistakes; the official description above is the record.